module-puppetlabs-mysql/lib/puppet/parser/functions/mysql_deepmerge.rb
2013-09-25 10:38:08 -07:00

52 lines
1.8 KiB
Ruby

module Puppet::Parser::Functions
newfunction(:mysql_deepmerge, :type => :rvalue, :doc => <<-'ENDHEREDOC') do |args|
Recursively merges two or more hashes together and returns the resulting hash.
For example:
$hash1 = {'one' => 1, 'two' => 2, 'three' => { 'four' => 4 } }
$hash2 = {'two' => 'dos', 'three' => { 'five' => 5 } }
$merged_hash = mysql_deepmerge($hash1, $hash2)
# The resulting hash is equivalent to:
# $merged_hash = { 'one' => 1, 'two' => 'dos', 'three' => { 'four' => 4, 'five' => 5 } }
When there is a duplicate key that is a hash, they are recursively merged.
When there is a duplicate key that is not a hash, the key in the rightmost hash will "win."
ENDHEREDOC
if args.length < 2
raise Puppet::ParseError, ("mysql_deepmerge(): wrong number of arguments (#{args.length}; must be at least 2)")
end
result = Hash.new
args.each do |arg|
next if arg.is_a? String and arg.empty? # empty string is synonym for puppet's undef
# If the argument was not a hash, skip it.
unless arg.is_a?(Hash)
raise Puppet::ParseError, "mysql_deepmerge: unexpected argument type #{arg.class}, only expects hash arguments"
end
# Now we have to traverse our hash assigning our non-hash values
# to the matching keys in our result while following our hash values
# and repeating the process.
overlay( result, arg )
end
return( result )
end
end
def overlay( hash1, hash2 )
hash2.each do |key, value|
if( value.is_a?(Hash) )
if( ! hash1.has_key?( key ) or ! hash1[key].is_a?(Hash))
hash1[key] = value
else
overlay( hash1[key], value )
end
else
hash1[key] = value
end
end
end